The reabsorption of a secreted substance by the cell that originally produced and secreted it. The process of reuptake, for example, affects serotonin.
Serotonin is a neurotransmitter (a chemical messenger). It is produced by nerve cells in the brain and is used by nerves to communicate with one another. A nerve releases the serotonin that it has produced into the space surrounding it. The serotonin either travels across that space and attaches to receptors on the surface of nearby nerves or it attaches to receptors on the surface of the nerve that produced it, to be taken up by the nerve, recycled, and released again. This process is referred to as reuptake. A balance is reached for serotonin between attachment to the nearby nerves and reuptake. A medication that acts as a selective serotonin reuptake inhibitor (SSRI) blocks the reuptake of serotonin and thereby changes the level of serotonin in the brain.
Reuptake is sometimes written as re-uptake.
- Reversal of organs, total
This condition (medically called situs inversus totalis) involves complete transposition (right to left reversal) of the thoracic and abdominal organs. The heart is not in its usual position in the left chest, but is on the right. Specifically related to the heart, this is referred to as dextrocardia (literally, right-hearted).The stomach, which is normally in […]
- Reverse genetics
In molecular genetics, identifying genes purely on the basis of their position in the genome, with no knowledge whatsoever of the gene product. In classic genetics, the traditional approach was to find a gene product and then try to identify the gene itself. Also known as positional cloning.
- Reverse transcriptase
An enzyme that permits DNA to be made, using RNA as the template. A retrovirus, such as the HIV virus, can propagate itself by converting its RNA into DNA with reverse transcriptase.
- Reye syndrome
A sudden, sometimes fatal, disease of the brain (encephalopathy) with degeneration of the liver, occurs in children (most cases 4-12 years of age), comes after the chickenpox (varicella) or an influenza-type illness, is also associated with taking medications containing aspirin. The child with Reye (pronounced rye) syndrome first tends to be unusually quiet, lethargic (stuporous), […]
Radio frequency identification, a system for remotely storing and retrieving data. RFID tags can serve to identify and track medications.